This invention relates generally to outside filling supply looms in which a small projectile is utilized to carry the filling yarn to the warp shed from supply packages located outside of the loom. The present invention is particularly directed to looms of the type in which filling yarn is inserted alternately from each side of the loom such as in the loom disclosed in U.S. Pat. No. 3,831,640 to Karl W. Wueger issued Aug. 27, 1974. In this loom, a projectile is launched from a launching and receiving apparatus at one side of the loom to a launching and receiving apparatus at the opposite side of the loom. Each launching and receiving apparatus contains a bore for receiving the projectile, a pressure chamber connected to the bore and a passageway leading from the bore to an outside opening. Filling yarn from an outside supply package enters the outside opening and extends to the bore through the passageway. Means is provided for inserting at least a portion of a filling pick into the projectile and pressurizing the pressure chamber to launch the projectile through the warp shed. Although most of the pressurized air escapes through the bore behind the launched projectile, a certain amount of "back pressure" extends through the passageway toward the outlet opening. This "back pressure" causes filling yarn to be blown toward the outer opening. Pressure is also created in the passageway when the projectile is received from the opposite side of the loom. As the incoming projectile is received into the bore, there is a pressure build-up which causes an air flow in the passageway toward the outer opening. At this point in the weaving cycle, the free end of the filling yarn is precisely positioned adjacent the bore in readiness for insertion into the projectile. The air flow caused by the incoming projectile causes this free end to be displaced, thereby seriously affecting the subsequent projectile loading step. This air flow may also cause the filling to be blown out of the outer opening which would necessitate stopping the loom for reinsertion of the filling yarn into the launching and receiving apparatus. These and other difficulties experienced with the prior art devices have been obviated by the present invention.
It is, therefore, a principal object of the present invention to provide a projectile launching and receiving apparatus for a pneumatic loom in which the effects of "back pressure" are obviated during the launching and receiving phases of a weft inserting cycle.
Another object of the invention is the provision of a valve which is effective to block the yarn passageway in the projectile launching and receiving apparatus to prevent air flow toward the outer opening of the apparatus.
A further object of the present invention is the provision of a valve closure element movable into the yarn passageway of a projectile launching and receiving apparatus which does not damage the yarn or otherwise interfere with normal feed of the yarn within the passageway.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.